Comparison of azosemide and furosemide in ascitic patients without and during administration of spironolactone.

Clinical, pharmacodynamic, and renal effects of a new diuretic, azosemide, were studied and compared with those of furosemide. Graded single intravenous (100-1600 mg) or peroral (100-400 mg) doses were administered to six patients with ascites due to liver cirrhosis without and during basic treatment with spironolactone. A standard peroral dose (160 mg) of both diuretics was found to have similar effectiveness. There was no difference in the time-course of action as determined on the basis of 24-h urine volume, sodium excretion, and osmolal clearance in four patients during basic treatment with spironolactone. However, azosemide appeared to be more effective than furosemide in those patients in whom a dose-response curve was established. Unlike furosemide, azosemide was much more effective when given intravenously than orally. Our study confirmed that azosemide is a "loop diuretic" with renal sites of action similar to those of furosemide. However, it has a higher efficiency, probably due to the steeper dose-response relationship.